Breast cancer surgery is the most common treatment for early stage breast cancer. Surgical options include breast removal (mastectomy) or breast conserving surgery (lumpectomy with radiation therapy). Long-term survival is similar with both surgical treatments.

Researchers analyzed data from more than 57,800 women across Canada who had breast cancer surgery between 2007 to 2008 and 2009 to 2010. Patients younger than 49 and older than 70 had a higher mastectomy rate (48 percent) than middle-aged patients (40 percent).

Mastectomy rates were highest in Newfoundland and Labrador at 69 percent and lowest in Quebec at 26 percent, according to the study published in the June 17 Canadian Medical Association Journal online.

The farther away breast cancer patients lived from radiation facilities, the more likely they were to have a mastectomy. The researchers also found that the richest women were less likely to have a mastectomy than the poorest women -- 39 percent vs. 49 percent.

Among women who had lumpectomy, 23 percent underwent surgery a year later to remove cancerous tissue. However, this rate varied substantially depending on the province or territory where patients lived.

About 6 percent of patients who had the breast with cancer removed also later had their other breast removed as a preventive measure, which is about half the rate in the United States.

The findings are "an important first step in understanding how care can be improved," according to Dr. Geoff Porter in a journal news release. Porter is chair of surgical oncology and professor of surgery at Dalhousie University in Nova Scotia.